Tyrosine is a natural amino acid - one of the building blocks of protein. It is required for the manufacture of the brain chemicals (neurotransmitters) dopamine and noradrenaline. These neurotransmitters are required for concentration, alertness, memory and a happy, stable mood.

Cautions and contraindications: Tyrosine supplements must not be used by people taking a type of antidepressant medication called Monoamine Oxidase Inhibitors (MAOIs). Examples of these drugs include Nardil (phenelzine), Parnate (Tranylcypromine), Selgene and Eldepryl (selegiline). Tyrosine can cause a severe rise in blood pressure in people taking these medications.